Hi, here are updated scores. https://lnt.opensuse.org/db_default/v4/SPEC/latest_runs_report?younger_in_days=14&older_in_days=0&all_elf_detail_stats=on&min_percentage_change=0.001&revisions=9388fc7bf0da61a8104e8501e5965120e9159e12%2Cea21f32198432a490dd490696322838d94b3d3b2%2C4f5431c5768bbba81a422f6fed6a6e2454c700ee%2C&include_user_branches=on compares base: mainline 1st column: mainline with very cheap vectorization at -O2 and -O3 2nd column: mainline with cheap vectorization at -O2 and -O3. The short story is: 1) -O2 generic performance kabylake (Intel): very cheap SPEC/SPEC2006/FP/total ~ 8.32% SPEC/SPEC2006/total -0.38% 4.74% SPEC/SPEC2006/INT/total -0.91% -0.14% SPEC/SPEC2017/INT/total 4.71% 7.11% SPEC/SPEC2017/total 2.22% 6.52% SPEC/SPEC2017/FP/total 0.34% 6.06% zen SPEC/SPEC2006/FP/total 0.61% 10.23% SPEC/SPEC2006/total 0.26% 6.27% SPEC/SPEC2006/INT/total 34.006 -0.24% 0.90% SPEC/SPEC2017/INT/total 3.937 5.34% 7.80% SPEC/SPEC2017/total 3.02% 6.55% SPEC/SPEC2017/FP/total 1.26% 5.60% 2) -O2 size: -0.78% (very cheap) 6.51% (cheap) for spec2k2006 -0.32% (very cheap) 6.75% (cheap) for spec2k2017 3) build times: 0%, 0.16%, 0.71%, 0.93% (very cheap) 6.05% 4.80% 6.75% 7.15% (cheap) for spec2k2006 0.39% 0.57% 0.71% (very cheap) 5.40% 6.23% 8.44% (cheap) for spec2k2017 here I simply copied data from different configuratoins So for SPEC i would say that most of compile time costs are derrived from code size growth which is a problem with cheap model but not with very cheap. Very cheap indeed results in code size improvements and compile time impact is probably somewhere around 0.5% So from these scores alone this would seem that vectorization makes sense at -O2 with very cheap model to me (I am sure we have other optimizations with worse benefits to compile time tradeoffs). However there are usual arguments against: 1) Vectorizer being tuned for SPEC. I think the only way to overcome that argument is to enable it by default :) 2) Workloads improved are more of -Ofast type workloads Here are non-spec benchmarks we track: https://lnt.opensuse.org/db_default/v4/CPP/latest_runs_report?younger_in_days=14&older_in_days=0&min_percentage_change=0.02&revisions=9388fc7bf0da61a8104e8501e5965120e9159e12%2Cea21f32198432a490dd490696322838d94b3d3b2%2C4f5431c5768bbba81a422f6fed6a6e2454c700ee%2C&include_user_branches=on I also tried to run Firefox some time ago. Results are not surprising - vectorizaiton helps rendering benchmarks which are those compiler with aggressive flags anyway. Honza
